This invention relates to buildings formed at least partly of concrete, techniques for erecting such buildings and components thereof.
In one class of building in which concrete is used, at least partly precast concrete columns are erected and at least partly precast concrete beams are mounted to the columns. Joists or panels are then mounted side by side to the beams to form a continuous floor.
In one prior art type of concrete building of this class, columns are erected with spaces void of concrete in the columns at the level of beams such as at each floor in a multistory building. The beams are mounted adjacent to the void spaces, Reinforcing rods extend through the void spaces and cast-in-place concrete later fills the void spaces to form a joint, but initially there is no concrete therein. The beams are partly precast concrete and partly cast-in-place concrete and the joists are hollow concrete panels.
In this type of prior art building, the beams are initially supported by temporary shoring adjacent to the columns and the joists are positioned to connect the beams one to the other. The beams are hollow and of uniform cross section throughout their entire length. Cast-in-place concrete is utilized to connect the beams, joists and columns to form an integrally connected structure.
This prior art type of building has several disadvantages, such as: (1) it requires temporary shoring during its erection which is an added expense; (2) it requires a relatively large depth in the precast beams, thus increasing the height and cost of a building; (3) it requires a relatively large amount of cast-in-place concrete; and (4) it requires a relatively long time period of heavy equipment use for lifting beams and the like in place.
Under some circumstances, it is desirable to construct a building of entirely precast concrete. This can reduce the cost by reducing the amount of time that cranes are necessary and thus substantially reduce the cost of multistory buildings.